Many various kinds of heat transfer walls for heat exchangers are known to the art. For example, there is described and illustrated in German Patent Specification No. 2343523 a tube through which a liquid is conducted and the wall of which presents a multiple of helically positioned channels, through which fine orifices communicate with the surroundings within which the tube is located.
Another type of heat transfer element is found described in U.S. Pat. No. 4,434,842, this element comprising a base plate on which there are welded two corrugated aluminium plates which partly overlap one another and which are provided with a large number of apertures.
The Japanese Patent Application No. 50-85333 describes and illustrates a thermal tube, the outer zone of which comprises a fibre mass having a large number of apertures up to the outer surface.
Many further examples of more or less complicated heat transfer elements are available in those patent classes to which the aforementioned inventions belong. The object of the present invention is, as indicated in the introduction, to provide a heat transfer element having a high heat transfer coefficient and which is of simple construction and of inexpensive manufacture.